Surface area to volume ratio

Question 1

State the formula for surface area to volume ratio

Answer 1

SA:V ratio = surface area ÷ volume

Question 2

What happens to surface area to volume ratio as a cell increases in size? Explain why this places a limit on the size of cells.

Answer 2

• As cell size increases, the SA:V ratio decreases.
• There means there is relatively less surface area per unit volume, resulting in the cell becoming less efficient at exchanging substances with the extracellular environment.